ucm2: HDA: Headphone output may be optional

Check for 'Headphone Playback Volume' or 'Headphone+LO Playback Volume'
controls. If they not present, don't create 'Headphone' UCM device.

Link: https://github.com/alsa-project/alsa-ucm-conf/issues/673
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

ucm2/HDA/HiFi-analog.conf

@@ -42,6 +42,14 @@ If.linefront {
 	}
 }
 
+If.hpvol {
+	Condition {
+		Type ControlExists
+		Control "name='Headphone Playback Volume'"
+	}
+	False.Define.hpvol ""
+}
+
 If.hplo {
 	Condition {
 		Type ControlExists
@@ -53,32 +61,38 @@ If.hplo {
 	}
 }
 
-SectionDevice."Headphones" {
-	Comment "Headphones"
-
-	If.headphone_switch {
-		Condition {
-			Type ControlExists
-			Control "name='Headphone Playback Switch'"
-		}
-		True {
-			EnableSequence [
-				cset "name='Headphone Playback Switch' on"
-			]
-			DisableSequence [
-				cset "name='Headphone Playback Switch' off"
-			]
-		}
+If.hp {
+	Condition {
+		Type String
+		Empty "${var:hpvol}"
 	}
+	False.SectionDevice."Headphones" {
+		Comment "Headphones"
 
-	Value {
-		PlaybackPriority 200
-		PlaybackPCM "hw:${CardId}"
-		PlaybackMixerElem "${var:hpvol}"
-		PlaybackMasterElem "Master"
-		PlaybackVolume "${var:hpvol} Playback Volume"
-		PlaybackSwitch "Headphone Playback Switch"
-		JackControl "${var:hpjack}"
+		If.headphone_switch {
+			Condition {
+				Type ControlExists
+				Control "name='Headphone Playback Switch'"
+			}
+			True {
+				EnableSequence [
+					cset "name='Headphone Playback Switch' on"
+				]
+				DisableSequence [
+					cset "name='Headphone Playback Switch' off"
+				]
+			}
+		}
+
+		Value {
+			PlaybackPriority 200
+			PlaybackPCM "hw:${CardId}"
+			PlaybackMixerElem "${var:hpvol}"
+			PlaybackMasterElem "Master"
+			PlaybackVolume "${var:hpvol} Playback Volume"
+			PlaybackSwitch "Headphone Playback Switch"
+			JackControl "${var:hpjack}"
+		}
 	}
 }